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RE: Radiation Hormesis -- or not
So far several people have commented that hemophilia
is an adverse factor and provides a selection fractor
that favors women over men. Bummer.
--- "Flanigan, Floyd" <Floyd.Flanigan@nmcco.com>
wrote:
> Perhaps hemophilia was an adverse adaptation to
> combat arterial plaque or blood clots which has side
> effects which outweigh the benefit of said
> adaptation?
>
> Floyd W.FlaniganB.S.Nuc.H.P.
>
> -----Original Message-----
> From: John Jacobus [mailto:crispy_bird@YAHOO.COM]
> Sent: Tuesday, January 27, 2004 8:21 AM
> To: Catherine Perham
> Cc: 'radsafe@list.Vanderbilt.Edu'
> Subject: RE: Radiation Hormesis -- or not
>
>
> Catherine
> I would also say that not all negative mutations are
> selected against survival. There are a number of
> genetic diseases that do not improve the species,
> e.g.
> hemophilia, but are still present and are passed
> along. It escapes me what was the evolutionary or
> genetic process that allowed it to exist in humans.
>
> --- Catherine Perham <cperham@ehso.emory.edu> wrote:
> > John;
> >
> > Genetic effects are completely random and as you
> > mention cannot be "willed."
> > We only see the positive genetic mutations such as
> > opposable thumbs because
> > all of the negative mutations were selected
> against-
> > in other words, they
> > died. Random effects are very unlikely to be
> > positive and that is why
> > evolution takes so long. Most mutations change a
> > protein structure such as
> > a hormone that may render it unusable to the
> > organism.
> >
> > My theory on the relative strength of the
> seedlings
> > in the experiment in
> > question is that the radiation killed off various
> > fungi and viruses that may
> > have lived on the seeds, and not a favorable
> > mutation within the seed
> > itself. After all, a dormant seed is not made up
> of
> > actively dividing
> > cells.
> >
> > Cheers;
> > Catherine
> >
> > -----Original Message-----
> > From: John Jacobus [mailto:crispy_bird@YAHOO.COM]
> > Sent: Monday, January 26, 2004 4:17 PM
> > To: Neil, David M; Carl Speer;
> > radsafe@list.Vanderbilt.Edu
> > Subject: RE: Radiation Hormesis -- or not
> >
> >
> > Why would a genetic mutation favor a negative
> > effect?
> > After all, evolution shows that genetic effects
> are
> > positive since they allow the organism to adapt.
> > Primates did not get opposed thumbs by willing it
> to
> > happen. It was genetics.
> >
> > Again, my statement was that it should have been
> > checked to see if it was a genetic mutation by
> > following the growth pattern of the off-spring.
> >
> > --- "Neil, David M" <neildm@id.doe.gov> wrote:
> > > If it were a genetic mutation, the odds favor
> > > (immensely) a negative effect. This would
> > translate
> > > to lower germination ratios (live plants per
> seed
> > > planted) and a mixture of positive and negative
> > > effects. This is not what is observed.
> > >
> > > Dave Neil
> > >
> > > -----Original Message-----
> > > From: John Jacobus
> [mailto:crispy_bird@yahoo.com]
> > > Sent: Friday, January 23, 2004 7:09 AM
> > > To: Carl Speer; radsafe@list.vanderbilt.edu
> > > Subject: RE: Radiation Hormesis -- or not
> > >
> > >
> > > Carl,
> > > A thought came to me. How do you know this was
> a
> > > hormetic effect and not a genetic mutation? My
> > > understanding is the a hometic effect involves
> the
> > > addition of some simulus to an living organism
> to
> > > get
> > > a beneficial response. You irradite mice to low
> > > doses
> > > and you get a certain response, e.g., an
> increase
> > in
> > > the immune system. When the agent is stopped,
> the
> > > hormetic effect is no longer evident after a
> time.
> > > Maybe this definition for hormesis is too
> > limiting,
> > > but this is what I believe it is.
> > >
> > > Seeds are not actively growing or responding
> > > organisms. If you irradiated the growing plant,
> I
> > > would agree that would be be a way of
> > demonstrating
> > > a
> > > hormetic effect. Did you try and grow new
> plants
> > > from
> > > the seeds produced from the mature, irradiated
> > > plants?
> > > I think that would have demonstrated the effect
> > of
> > > genetic mutation.
> > >
> > > --- John Jacobus <crispy_bird@yahoo.com> wrote:
> > > > Interesting. What were the doses?
> > > >
> > > > --- Carl Speer <rtrs@cox.net> wrote:
> > > > > Karl (and others),
> > > > >
> > > > > We had and interesting laboratory experiment
> > in
> > > > > Radiation Biology when I
> > > > > was in college where we irradiated bean
> seeds,
> > > > fruit
> > > > > flies, and onion
> > > > > root with low, med, and high doses from a
> > Co-60
> > > > > source from a local
> > > > > hospital. To show the effects of hormesis,
> no
> > > > > effect, and ill effect
> > > > > the students all received seeds from each
> > > exposed
> > > > > group plus seeds that
> > > > > did not get any extra dose (controls). We
> > > planted
> > > > > the seeds in cups at
> > > > > our home, gave all plants the same amount of
> > > water
> > > > > and noted the
> > > > > differences. The seeds with the low doses
> had
> > > > more
> > > > > vigorous growth,
> > > > > smaller internodal lengths, and healthier
> > leaves
> > > > > than the control. The
> > > > > higher dose plants had brown shriveled
> leaves,
> > > > > stunted growth, and other
> > > > > undesirable characteristics. We made a plot
> > > > showing
> > > > > that as the dose
> > > > > initially increased we saw a net positive
> > effect
> > > > > (hormesis) but as the
> > > > > dose continued to increase, a negative
> effect
> > > > became
> > > > > apparent. This
> > > > > made a lasting impression and I have
> believed
> > in
> > > > > hormesis ever since. I
> > > > > know people are not bean plants or fruit
> flies
> > > but
> > > > > this little
> > > > > experiment gave the hormesis theory more
> > > > > believability than the LNT in
> > > > > my mind.
> > > > >
> > > > > As for the fruit flies I don't remember the
> > low
> > > > dose
> > > > > effects. What
> > > > > stands out in my memory were the horrific
> > > > mutations
> > > > > in the offspring of
> > > > > the high dose flies.
>
=== message truncated ===
=====
+++++++++++++++++++
"I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man."
Thomas Jefferson
-- John
John Jacobus, MS
Certified Health Physicist
e-mail: crispy_bird@yahoo.com
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